A hollow fiber membrane has many porous structures formed in the membrane in terms of its structure, so that it expands or contracts largely as a result of change of an external environment such as temperature. A hollow fiber membrane may be subjected to process such as filtration, condensation or degassing of a solvent in terms of its function. In this case, the material of the hollow fiber membrane itself may be swelled by the solvent.
A hollow fiber membrane module includes hundreds or thousands of such hollow fiber membranes housed in a bundling tube. Even though the contractile force of one hollow fiber membrane may be small, the contractile forces of all hollow fiber membranes housed in the bundling tube act on the bundling tube because all the housed hollow fiber membranes expand or contract. Thus, in the hollow fiber membrane module comprising including the bundling tube housing the hollow fiber membranes and potting parts formed at both ends of the bundling tube, expansion of the hollow fiber membranes in the longitudinal direction may make the hollow fiber membranes protrude from the bundling tube as a result of an integral structure of the bundling tube, the hollow fiber membranes may be pressed against a fence for prevention of the protrusion to be damaged, or the contraction of the hollow fiber membranes in the longitudinal direction may damage the hollow fiber membranes or the bundling tube.